Stabilized chlorofluoroalkane composition



United States Patent 3,445,527 STABILIZED CHLOROFLUOROALKANE COMPOSITION Kazuo Okamura, Itami-shi, Japan, assignor to Daikin Kogyo Kabushiki Kaisha, Kita-ku, Osaka-shi, Japan, a

juridical person of Japan No Drawing. Filed Jan. 16, 1967, Ser. No. 609,360 Claims priority, application Japan, Jan. 21, 1966,

41/3,402; June 3, 1966, 41/315,935 Int. Cl. C07c 19/08 U.S. Cl. 260652.5 7 Claims ABSTRACT OF THE DISCLOSURE Chlorofiuoroalkane based compositions containing trichlorofluoromethane, trichlorotrifiuoroethanes or tetrachlorodifiuoroethanes are stabilized against reaction with 85 to 95 volume percent hydrated alcohol having 1 to 4 carbon atoms by 0.1 to 5.0 weight percent of one or more epoxyethane compounds which are epoxyethane, 2-methyl-1,2-epoxyethane, 2-vinyl-1,2-epoxyethane and 2-methyl-2-vinyl-1,2-epoxyethane. The compositions may also contain nitromethane as an added stabilizer. Said compositions are particularly useful as aerosol compositions and solvent media for cleaning.

The product, acetaldehyde, emits a disagreeable odor and produces a colored and odoriferous condensation products, and hydrogen chloride is corrosive to metals, producing insoluble metallic salts and hydrogen. In aerosol formulations such products are harmful to the human body, and are objectionable for their disagreeable odor, coloration and corrosion of metallic containers. Further, in the cleaning formulations such products are also objectionable as well as harmful to the human body.

The problems discussed above are intensified particularly when 85-95 volume percent hydrated alcohol is used. For example, an aerosol product in which hydrated alcohol is used produces more objectionable odor, is more discolored and corrodes metallic containers more rapidly than an aerosol product made with anhydrous alcohol. The reason for the acceleration of such phenomena by the use of hydrated alcohol is not clear, but such is presumed to be due to the fact that chlorofiuoroalkane not only reacts with alcohol but also produces acidic substances by hydrolysis reaction. This reasoning may be proved to some extent by the fact that the pH of a composition containing hydrated alcohol is reduced more rapidly and markedly than one containing anhydrous alcohol. However, since 85-95 volume percent hydrated alcohol is lower in cost than anhydrous alcohol and less stimulative to human skin, hydrated alcohol is more desirably useful for the preparation of the chlorofiuoroalkane composition.

U.S. Patent No. 3,085,116 discloses that mononitroal- "ice kanes are eifective in inhibiting the above reaction of chlorofluoroalkanes with anhydrous alcohols. In fact, when anhydrous alcohol is used, nitroalkanes effectively inhibit the above reaction, while when hydrated alcohol is used the effect is not so marked. Particularly, less than 0.1 weight percent of nitroalkane based on the weight of chlorofiuoroalkane exhibits almost no inhibiting efiect on the reaction of chlorofiuoroalkane with hydrated alcohol. Furthermore, nitroalkanes are rather expensive compounds, and the use of larger amounts is not desirable from an economical view point, and the use of larger amounts is also undesirable because of increased discoloration which results from the action of sunlight and ultraviolet light rays on such compositions.

An object of the invention is to provide a chlorofiuoroalkane composition which is stable even to hydrated aliphatic alcohol.

Another object of the invention is to provide inhibitors which eifectively inhibit the reaction of ch1orofluoroalkanes with hydrated aliphatic alcohols.

A further object of the invention is to provide a chlorofiuoroalkane composition which is free for a long period of time from disagreeable odor and discoloration and the formation of substances harmful to the human body.

A further object of the invention is to provide a chlorofiuoroalkane composition which is not discolored by the sun and ultraviolet rays and is economically advantageous.

' The foregoing and other objects of the invention will be clear from the description to follow.

The above objects of the invention may be accomplished by a composition being stable to to volume percent hydrated aliphatic alcohol having 1 to 4 carbon atoms which comprises a chlorofiuoroalkane of the group consisting of trichlorofluoromethane, trichlorotrifluoroethanes and tetrachlorodifluoroethanes and 0.1 to 5 weight percent of an epoxyethane compound of the group consisting of epoxyethane, 2-methyl-1,2-epoxyethane, 2-vinyl- 1,2-epoxyethane and 2-methyl-2-vinyl-1,2-epoxyethane; or comprises said chlorofiuoroalkane, 0.1 to 2.0 weight percent of said epoxyethane compound and 0.01-0.1 weight percent of nitromethane.

This invention is based on the discoveries that said epoxyethane compound effectively inhibits the reaction of chlorofiuoroalkane with hydrated alcohol for a long period of time and that when the epoxyethane compound is mixed with such slight amounts of nitrom'ethane which, alone, exhibit almost no inhibiting effect on the above reaction, the mixture exhibits high inhibiting elfect due to a synergistic action which is not expected in view of the,

activities of each of these substances individually.

The epoxyethane compounds to be used according to the invention are epoxyethane (C Hz-C Hz) 2-methyl- 1,2-epoxyethane (CHE-C HC H2) 2-vinyl-1,2-epoxyethane (C Hz=C H-C HC Hz) and 2-methyl-2-viny1-1,2-epoxyethane (3 Hz 0 Hz-C H-0 0 H2) and most desirable is Z-methyl-1,2-epoxyethane. These compounds are nonacidic,volatile, nontoxic and low in cost, and are free from disagreeable odor and color and are noncorrosive to metals and other materials with which the inhibiting effect will depend only upon such compound and the synergistic effect by the combined use with nitromethane will disappear. Nitromethane exhibits no adverse effect on the composition of the invention when the compositions of the invention will be brought into 5 used in the range of amounts recommended according to contact. This epoxyethane compound is used at a rate of the invention. 0.1-5 weight percent, preferably 0.5-3 weight percent, The chlorofluoroalkanes to be used in the invention inbased on the weight of chlorofluoroalkane, and the lower elude trichlorofluorornethane, 1,1,Z-trichloro-1,2,2-trifluois the amount of the epoxyethane compound which is roethane, 1,1,1-trichl0ro-2,2,Z-trifluoroethane, tetrachloused, the lesser is the effect. Larger amounts of epoxyro-l,2-difluoroethane and tetrachloro-2,2,-difluoroethane. ethane compound may be used but are unnecessary and Among these compounds trichlorofiuoromethane is most tend to be uneconomical. widely used. Said chlorofluoroalkane is used as a propel- The above epoxyethane compound can singly inhibit 1at}t Q and also as a Solvent Cleanmg by the reaction of chlorofluoroalkane with hydrated alcohol, belng f Wlth y t alcohol h 1156? as a Pt but by addition of a slight amount of nitromethane to the Pellant thls Compound 18 mos-fly l 111 a IIllXtufe t lower range f h amounts f epoxyethane compound other propellants such as dichlorod fiuoromethane, d1- hi h can b used, h i hibi i f h above reaction is chlorotetrafiuoroethane, monochlorodifluoromethane, 1,1- markedly increased. In this case, it is desirable to use dlfluoroethane:PrPaI1e,butaI1e,t- 0.1-2.0 weight percent, preferably 0.51.5 weight er- The h drated alcohol used in the invention consists P 20 Y cent, of epoxyethane compound and 0.01-0.1 weight perof 85-95 volume percent of an aliphatic alcohol having cent, preferably 0.05-0.08 weight percent, of nitrometh- 1-4 carbon atoms such as methanol, ethanol, propanol, ane based on the weight of chlorofluoroalkane. By the iso ro anol, etc., and 5 to 15 volume percent of water.

e p p use of the above substances in the given range, a marked- Said hydrated alcohol 15 used as a solvent for both aerosol ly synergistic effect is exhibited. While the presence of and cleaning applications, of these alcohols, 95 volume about Welght Pfifcellt 0f Ilttromethane alone in percent ethanol is most desirable for the applications in chlorofluoroalkane can hardly inh1b1t the undesirable question l hol if ggfi gf g ii g z ji gi f m g gfifg g The epoxyethane compound and nitromethane to be 2 ation with the 1 amount nitromsethine 0 used in the invention are both soluble in chlorofiuoroal- 3 markedly higher inhibiting effect is exhibited over the kanes '91 hydrtged fi g f g' i g ifi single use of epoxyethane compound of the same amount, or a mlxbure 5 g i 13 n th and as far as nitromethane is used within the above range, ane can e a 6 to t e c uoroa, f or e the composition of the invention is not discolored by the drated alcohol or to composltlon contammg one or both sun and ultraviolet rays, and has sufficient economical of the Chlorofiuoroalkane and t hydratett 31601101- advantages. The use of a larger amount of nitromethane NOW for a better ulndel'standlng 0f t lnventlon, the il l d to k d di b i b h Sun d u examples of the invention are tabulated in Table 1 below. violet rays and lowers economic features. A lower amount In t table the results Performed t0 detefmme of nitromethane loses the effect of the combination. By the inhibiting effect of the inhibitors of the present inventhe use of a larger amount of epoxyethane compound 40 tion are shown.

TABLE 1 Sample Wt. 01- No. Inhibitor percent (p.p.m.) pH Odor Corrosion 1-a 2-methyl-1,2-ep0xyethane 0.01 230 2.3 Pungent Severe. 1-b d0 0.05 100 2.8 Slightly Moderate.

pungent. 0.1 3.0 No ehange Slight. 0.5 14 4.3 do No change. 1.0 10 4.4 do Do. 3.0 5 5.0 do.- Do. 7.0 5 5.0 .do Do. 0.01 240 2.3 Pungent Severe. 0.05 110 2.8 Slightly Moderate.

pungent; 0. 1 3.1 No change. Slight. 1.0 40 3.4 do No change. 3.0 32 3.7 do.-. Do. 0.01 180 2.1 Pungent Severe 0.05 3.0 Slight. 0. 10 60 3. 2 No change.

0.5 s 4.7 Do. do 1.0 6 4.8 do Do. 4- 2-vgiyl-2-methyl-l,2-epoxye- 0.01 240 2.3 Pungent. Severe.

t 4-D 30D? 0.05 120 2.7 Slightly Moderate.

pungent. 0.1 85 3.0 No ehange Slight. 0.5 22 3.9 do No change. do 1.0 15 4.8 do Do. methyl-1,2-epoxyethane 0.10} 21 Nitromethane 0.05 5- 2-methyl-1,2-epoxyetha 0.50} 5 N itromethane- 0. 05 5-0 2-methyl-1,2-epo ha 3.00 5

Nitromethane 0.05 5d 2-methyl-l,2-epoxyethane 0. 10 10 N itromethane 0. 10 5-e 2-methyl-1,2-epoxyethane. 0.50 5

Nitromethane 0. 10 5- 2-methyl-1,2-epoxyethane 3.00 l 5 Nitromethane 0.10 J 6-a do 0. 05 Control 251 N OTE.Wt. percent of the inhibitor based on the weight of triehlorofiuoromethane.

5 In a 200 m1. tinplated aerosol container 50 g. of 95 volume percent ethanol, and 50 g. of trichlorofluoromethane were placed and to such mixture a prescribed amount of the inhibitor shown in the table was added, then the 6 percent ethanol in Table 2 and 85 volume percent ethanol in Table 3 were used, respectively, in place of 95 volume percent ethanol and the same tests were performed.

TABLE 2 Sample Wt. 01- No. Inhibitor percent (p.p.m.) pH Odor Corrosion 7-a 2-methy1-1-,2-epoxyethane 0. 1 B 3.0 No'change No change 7-b do 0. 40 3. 5 do Do. a a" 2 a 0...-.. 1 0.: 3-? Epogy i'hnnn 060; 13g lgiofirate.

0. 5 52 3. 3 No change. 1. 0 40 3. 5 Do. 3.0 4.0 Do. 0. 1 70 3. 1 D0. 0. 5 3. 7 D0. 1. 0 20 4. 0 D0. 3. 0 11 4. 4 D0. 0.05 200 2.4 Severe.

0.2 95 2.8 No change Slight. 0.5 60 3.2 No change. 1.0 46 3.4 D0. 3.1 2- 3. 3 25 3.8 met ",7 -1, N itromethane 8&5) 80 a 5 do 1. 3 26 3.8 3} is 4.1 0. 1 8} 3.2 0. 5 3} a0 3.1 20 4.0 sitfifiitih... 3:93} 15 12-a do .05 380 1.9 Pungent Severe. 12-b do 0. 10 300 2. 1 do Do. Control 500 1.7 do Very severe.

TABLE 3 Sample Wt. 01- No. Inhibitor percent (p.p.m.) pH Odor Corrosion 13-9. 2-methyl-l,2 epoxyethane 0.5 100 2.8 No change Slight. 1:3;- "go 3-0 .....(10 No change.

n D0. 14-11 2-vinyl-1,2-ep0xyethane 0. 5 90 Slight. 14b do 1. 0 75 No change i i t ;1 11 a th 0 6 5 70 a me y epoxye aue b g g fi l a 51T 3 3} 280 2.2 Pungent Severe. 15- me y -l,2.-e oxye ane .5

gg g g i ig 63 2.9 No change No change. 15-0 2-1ne y -1, e oxye a Nitromethane f 0. 0s 42 15-d 2-methyl-l,2-epoxyet 0.50 60 Nitromethane 0. 10 16-11 rln 0. 05 1, 000 16-h do 0. 1 800 Control 1, 030

container was sealed airtight and shaken to mix the contents thoroughly. The aerosol container thus prepared was kept in a room maintained at 60 C. for 4 weeks, after which the concentration of chlorine ion, pH, the odor of the solution and the condition of corrosion of the container were examined. The concentration of chlorine ion was sought by first cooling the container maintained at 60 C. to room temperature, then transferring the contents to a beaker, heating such contents at 40 C. to let the contained chlorofiuoroalkane vaporize, and after diluting the residue with an equivalent amount of water, titrating the thus diluted solution with silver nitrate solution. The pH value was determined by measuring the hydrogen ion concentration of said diluted solution with a Beckman pH meter. I

Other examples are given in Table 2 and Table 3 below, in which compositions were prepared by the same manner as the examples in Table 1 above except that 90 volume What I claim is:

1. A composition stable to to volume percent hydrated alcohol having 1 to 4 carbon atoms which comprises a chlorofiuoroalkane of the group consisting of trichlorofiuoromethane, trichlorotrifluoroethanes and tetrachlorodifluoroethanes and 0.1 to 5.0 weight percent of an epoxyethane compound of the group consisting of epoxyethane, 2-methyl 1,2 epoxyethane, 2 vinyl-1,2- epoxyethane and 2-methyl-2-vinyl-1,2-epoxyethane.

2. A composition according to claim 1, in which said chlorofiuoroalkane is trichlorofluoromethane.

3. A composition according to claim 1, in which said epoxyethane compound is Z-methyl-1,2-epoxyethane.

4. A composition according to claim 1, in which said epoxyethane compound is present in the amount of 0.5 to 3.0 weight percent, based on the weight of said chlorofluoroalkane. p

5. A composition according to claim 1, which contains 0.1 to 2.0 weight percent of said epoxyethane compound and 0.01 to 0.1 Weight percent of nitromethane, respectively, based on the weight of said chlorofluoroalkane.

6. A composition according to claim 5, in which said epoxyethane compound is Z-methyl-1,2-epoxyethane.

7. A composition according to claim 5, in which said epoxyethane compound is present in the amount of 0.5 to 1.5 weight percent and said nitromethane is present based on the weight of said chlorofluoroalkane.

References Cited UNITED STATES PATENTS 4/1963 Kualnes et a1 260-652.5 8/1966 Cormany 260652.5

LEON ZITVER, Primary Examiner.

M. M. JACOB, Assistant Examiner.

US. Cl. X.R. 536; 252-170 

